The objectives of this research are (1) to develop and standardize methods for vitro activation of promutagens by green plants; (2) to characterize plant activation and compare it with mammalian microsomal activation; (3) to incorporate in vitro plant activation products with microbial assays for mutagenicity; and (4) to compare the genetic activities of the promutagens assayed in objective three with in vivo mutation assay in whole plants. We originally developed the concept that plants could activate chemical promutagens into mutagens and suggested an environmental hazard may be present with respect to modern agricultural practices. This concept is based upon the principle that the plant activation system be separated from the genetic endpoint. In this research we shall specifically investigate if cell free plant tissue homogenates and a plant cell/microbe coincubation activation system can activate known chemical promutagens into mutagens. The genetic endpoints we will use include a primary DNA damage rec assay in Bacillus subtilus, foward and reverse mutation assays with Salmonella typhimurium and recombination and reverse mutation assays with Saccharomyces cerevisiae. Both cell free and plant cell activation systems will be evaluated and compared with mammalian S-9 liver preparations. Additionally, cell free and plant cell activation systems will be compared with whole plant genetic assays. The whole plant assays we will use are the waxy locus assay in maize microgametophytes, the yellow-green-2 assay in maize somatic tissues and the micronucleus test in tetrads of Tradescantia. Using etiolated and green seedlings this research would determine whether plant activated mutagens require photosynthetic processes, and by using a number of genetic endpoints determine modes of metabolism as well as a spectrum of genetic events. Considering the wide variety and large amounts of chemicals released into the environment, the information that would be generated by this proposed research will be useful in developing policies for the protection of the public health.